Methods and apparatus for intravenous therapy and hyperalimentation

ABSTRACT

Methods and apparatus for short term and long term intravenous therapy including hyperalimentation are disclosed. The proximal end of a flexible catheter having a one way valve adjacent its proximal end is inserted through the skin of a patient and into a vein having a suitably large flow of blood therethrough. The distal end of the catheter has a threaded male coupler for connecting it to a flow reducing adaptor and then to a source of intravenous solution. The solution flows by gravity through the catheter and into the vein. A passer which can be connected to the male coupler is provided for subcutaneously threading the catheter during long term catheter placement.

BACKGROUND OF THE INVENTION

The present invention relates to the intravenous administration ofnutrients and therapeutic agents to patients and, more particularly, tomethods and apparatus for administering intravenous hyperalimentation.

Ingestion, digestion, and absorption of food and assimilation ofresulting substrates into the body cell mass are vital functions of thegastrointestinal tract. These functions may be impaired in a variety ofways. For example, infants born with gastrointestinal abnormalities,adults who develop gastrointestinal diseases, burn or accident victims,cancer patients, etc., may be unable to maintain their nutritional andfluid balance by oral intake. Without proper treatment they may die fromstarvation and dehydration.

Traditional intravenous feeding, i.e., through relatively small veins inthe limbs, has severe limitations. A patient with one of the abovedescribed maladies may initially require eight liters or more ofintravenous fluid per day with enough fats, proteins, and carbohydratesto meet the body's nutritional requirements and maintain positivenitrogen balance. Beyond three liters per day, however, the excess fluidstrains the cardiovascular system. A diuretic may be given so that thekidneys can process the additional fluid. However, this method isdangerous.

Another approach is to increase the concentration of nutrients in theintravenous solutions. However, such solutions cannot be dripped into arelatively small vein in the arm or leg without severe pain coupled withthe risk of vein inflammation and/or thrombosis.

In the early 1960's Dr. Stanley J. Dudrick and his colleagues developeda method of intravenous nutritional support (referred to in the medicalprofession as a hyperalimentation or total parenteral nutrition) bywhich normal growth and development as well as a positive nitrogenbalance could be maintained. An open ended catheter was threaded througha moderate sized vein such as the subclavian, accessible under thecollarbone, and into a very large vein, the superior vena cava. Becauseof the very large flow of blood through the superior vena cava aconcentrated solution delivered through the catheter is rapidly diluted,thus allowing administration of a high concentration of nutrientswithout risk of pain, venous inflammation, or thrombosis.

Since Dr. Dudrick's initial work extensive research and development hasbeen done with intravenous nutritional solutions. It has been possibleto supply up to 7000 calories per day intravenously. Different apparatusand methods have evolved for short and long term intravenous therapy.With the latter, the distal end of the catheter is routed subcutaneouslyto an exit point midway down the anterior wall of the chest. The patientcan then couple the catheter to a source of nutrients in the home andthus avoid prolonged hospitalization while still obtaining intensiveintravenous nutritional therapy.

Serious problems heretofore encountered with hyperalimentation includepotentially fatal air embolism which may occur when the distal end ofthe catheter becomes disconnected; severe or fatal hemorrhage which mayalso occur if the end of the catheter becomes disconnected; and bloodreflux into the open proximal end of the catheter which may result inblood clots which interfere with and stop the flow of intravenoussolution through the catheter. These clots may also form the nidus forbacterial or fungal growth which may then give rise to serious or fatalsepticemias. If blood clots from the catheter enter the circulatorysystem the consequences may be serious or fatal. Therefore, it has beennecessary to flush out the catheter with an anticoagulant as often asevery four hours.

In order to avoid metabolic disorders due to excesses or deficiencies inthe administration of intravenous nutritional therapy it is necessary tocontrol the amounts of nutrients and fluids supplied. Heretofore, everyknown apparatus for intravenous hyperalimentation has utilized costlypumps and flow sensing devices for controlling the rate of fluidadministration, both to prevent too rapid administration which wouldresult in severe metabolic disorders, and to prevent flow stoppage whichmay result in clotting in the catheter, making it unusable. Aphotoelectric sensor or some other device must be used to shut off thepump when the solution bottle has emptied otherwise a serious andpossibly fatal air embolus will occur. If the pump is non-operative forjust a short period of time, blood will reflux into the open proximalend of the catheter, causing a blood clot which may render the catheterinoperative or lead to other previously described complications.

Other problems involve the amount of hardware which must remain coupledto the distal end of the catheter after insertion. This inhibits thepatient's mobility and increases the risk of accidental dislodgement,kinking, or cutting of the catheter. Furthermore, if intravenous therapyis temporarily suspended, the catheter must be flushed with ananticoagulant solution as frequently as every four hours to preventblood clots from forming in the catheter. Finally, methods of passingthe catheter through the subcutaneous tissue for permanent placementhave been cumbersome and require separate tunnelling and threadingprocedures.

Catheters with one way valves adjacent their closed proximal ends havebeen used to deliver cerebrospinal fluid to the atrium of the heart.However, catheters with proximal one way valves have not heretofore beenutilized to accomplish intravenous administration of nutrients ortherapeutic agents, including total parenteral nutrition.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide methods andapparatus for intravenous administration of nutrients or therapeuticagents, including total parenteral nutrition, that will substantiallyeliminate any risk of loss of blood through the catheter as well asproblems resulting from the formation of blood clots inside or outsidethe catheter.

It is another object of the present invention to provide methods andapparatus for intravenous administration of nutrients and therapeuticagents, including total parenteral nutrition, which will reduce theincidence of infection in, on, or around the catheter.

It is another object of the present invention to provide methods andapparatus for administration of nutrients or therapeutic agents,including total parenteral nutrition, that will substantially reduce therisk of air embolism.

It is a further object of the present invention to provide methods andapparatus for intravenous administration of nutrients or therapeuticagents, including total parenteral nutrition, which do not require pumpsand other complex flow control devices.

It is yet a further object of the present invention to provide methodsand apparatus for intravenous administration of nutrients or therapeuticagents including total parenteral nutrition, such that any equipmentused to insert the catheter, other than the catheter itself, can beeasily and completely removed after insertion of the catheter.

It is another object of the present invention to allow intermittenttemporary termination of intravenous therapy, including total parenteralnutrition, with disconnection from the source of intravenous therapywithout the danger of catheter occlusion by blood clots and without theneed for repeated flushing with heparin or other anticoagulantsubstances.

It is yet another object of the present invention to allow determinationof the venous pressure, preferably in the superior vena cava (centralvenous pressure) of the vessel the catheter tip is positioned in withoutallowing blood reflux into the catheter and without the need foradditional apparatus or manometers.

It is a further object of the present invention to allow easysubcutaneous passage of the catheter utilizing a passer which can bereadily connected to the distal end of the catheter and used tosimultaneously form a subcutaneous tunnel and thread the cathetertherethrough.

According to the present invention the proximal end of a flexiblecatheter having a one way valve or valves adjacent its proximal end isinserted through the skin or through a surgical incision in the skin ofa patient and into a vein having a suitably large blood flowtherethrough. The catheter preferably has a coating of heparin or otheranticoagulant substance on its internal and external surfaces,radiopaque markings and metric indicia, and a removable internalstiffener. The distal open end of the catheter has a male threadedfitting or coupler which is threadably coupled to a flow reducingadaptor which is, in turn, coupled to a source of intravenous fluidhaving the desired concentration of nutrients or therapeutic agents, viaa standard intravenous drip connector. All extraneous apparatusnecessary for the insertion of the catheter is easily removed afterinsertion. The intravenous solution flows by hydrostatic pressurethrough the catheter and into the vein, the maximum flow rate beinglimited to a safe level by the valve and by the flow reducing adaptor.The venous pressure inside the vein (venous pressure) is easilydetermined by finding the fluid pressure at which flow just stops andsubtracting the opening pressure of the catheter valve or valves. Thecatheter may be intermittently disconnected from the source ofintravenous fluids and capped without danger of blood clots forming inor on the catheter. A tubular passer can be readily connected to themale coupler at the distal end of the catheter and used tosimultaneously form a subcutaneous tunnel and retrogradedly thread thecatheter therethrough.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A is a fragmentary view of the catheter forming a part of theshort term intravenous therapy apparatus of the present invention. Shownin FIG. 1A are the removable internal stiffner and the threaded malecoupler at the distal end of the catheter which threadably engages theflow reducing adaptor;

FIG. 1B is a fragmentary view of the catheter forming a part of the longterm intravenous therapy apparatus of the present invention. The one wayvalve at the proximal end of the catheter is shown open or expandedwhich occurs when fluid inside of the catheter is at a pressuresufficienty greater than that outside of the catheter. Also shown inFIG. 1B is the cuff which surrounds the catheter and is imbedded in thesubcutaneous tissue near the point where the catheter exits the body;

FIG. 2A shows the flow reducing adaptor which is threadably engaged withthe male coupler at the distal end of the catheter. A cap may be screwedover the distal end of the adaptor to seal the same;

FIG. 2B shows the standard male fitting of an intravenous drip mechanisminserted into the distal end of the adaptor;

FIG. 3A shows a hypodermic needle and a sleeve which fits over the same,both forming part of the short term intravenous therapy apparatus. Thehypodermic needle hub accepts the male fitting of a standard syringe;

FIG. 3B shows a fragmentary view of the catheter of FIG. 1A being guidedthrough the sleeve of the short term intravenous therapy apparatus withthe aid of the internal stiffner;

FIG. 4A shows a fragmentary view of the passer forming a part of thelong term intravenous therapy apparatus;

FIG. 4B shows the manner in which the passer of FIG. 4A is connected tothe distal end of the catheter of FIG. 1B;

FIGS. 5A-5D are simplified anatomical views of a patient illustratingthe manner in which the short term intravenous therapy orhyperalimentation apparatus is utilized; and

FIGS. 6A-6H are simplified anatomical views of a patient illustratingthe manner in which the long term intravenous therapy orhyperalimentation apparatus is utilized.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The term `proximal end` when used in reference to a needle, sleeve, orcatheter, refers to the forward end thereof which is inserted into thepatient's body. The term `distal end` when used in reference to aneedle, sleeve, or catheter, refers to the rearward end thereof which issituated externally of the patient's body.

According to the present invention, the apparatus utilized to performshort term intravenous therapy or hyperalimentation has certainmechanical elements in common with the apparatus utilized to performlong term intravenous therapy or hyperalimentation. Specifically, bothpreferably include a flexible catheter having a one way valve or valvesadjacent its proximal end, internal and external coatings of heparin orother anticoagulant substance, radiopaque markings and metric indicia, amale threaded coupler at the distal end of the catheter, a removableinternal stiffener, and a flow reducing adaptor which threadedly engagesthe male coupler at the distal end of the catheter and which accepts themale fitting of a standard intravenous drip mechanism at its distal end,and may threadedly accept a cap at its distal end when intravenoustherapy is temporarily interrupted. In addition, the short termintravenous therapy apparatus includes a syringe, needle, and externalsleeve which are hereafter described. The long term apparatus includes apasser and a DACRON (trademark) cuff which is hereafter described.

Referring to FIG. 1A, the catheter 10 which is to be inserted into thepatient is made of a durable, flexible, biocompatible material such as,but not necessarily, silicon rubber. One suitable material is sold underthe registered trademark SILASTIC. Preferably the catheter istranslucent so that the physician can determine the presence of airbubbles within the catheter. When used for short term intravenoustherapy, the catheter preferably has sufficient length to extend fromthe skin of the patient to a vein which will not be adversely affectedby the intravenous therapy or therapeutic agent administered. In thecase of administration of concentrated hyperalimentation fluids, thislength should be sufficient to extend from the site of insertion to thesuperior vena cava. The length will depend upon the size of the patientand the intended therapy to be administered. When used for long termintravenous therapy or hyperalimentation, the catheter preferably hassufficient length to extend from the superior vena cava to thedeltopectoral groove or anterior lateral neck and further to a pointmidway down the anterior wall of the chest.

The catheter must have a relatively small outside diameter so that itcan be readily inserted into a vein, such as the subclavian vein,without causing undo trauma to the vein and the surrounding tissues.Preferably the catheter has an outside diameter no greater than fourmillimeters. The inside diameter of the catheter must be large enough topermit intravenous solution to flow therethrough at a rate sufficient toallow the required amount of nutrients or therapeutic agents to bedelivered. An example of a suitable size is an outside diameter of 2.2mm and an inside diameter of 1.3 mm.

The catheter has a one way valve 12 (FIG. 1A) adjacent its proximal end.The valve may be formed by one or more individual slits precisely cutinto the catheter wall. Multiple slits may be circumferentially spaced.As shown in FIG. 1B, the valve 12 opens when the fluid pressure insidethe catheter is greater than the fluid pressure outside the catheter bya predetermined amount. The minimum amount of pressure needed to openthe valve may be varied from catheter to catheter by varying the numberof slits, length of the slits, the thickness of the catheter wall, orthe elasticity of the catheter wall. A catheter with this type of oneway valve will resist retrograde flow of fluids into the proximal end ofthe catheter. That is, when the hydrostatic pressure inside the catheteris greater than the pressure outside the catheter by a given amount, theopening(s) defined by the slit(s) 12 will expand (FIG. 1B), therebyallowing fluid to flow out of the catheter. However, when there is fluidpressure outside the proximal end of the catheter which is greater thanthe fluid pressure inside the catheter, the valve opening(s) will closeand prevent retrograde flow into the catheter. One suitable catheter isthe PUDENZ (trademark) cardiac catheter manufactured by Heyer Schulte,Inc., a subsidiary of American Hospital Supply Export Corporation. It isavailable in several different valve opening pressures.

The catheter preferably has a coating 13 of anticoagulant substances,such as sodium heparin, on its internal and external surfaces to preventthe formation of blood clots thereon. The surfaces defined by theslit(s) 12 should preferably be coated in this manner to prevent bloodclots from forming on the valve opening(s).

The proximal end 14 (FIG. 1A) is preferably pointed to facilitateinsertion and advancement of the catheter in the vein. It may contain aquantity of radiopaque material 15, such as barium sulfate, so that theposition of the proximal end of the catheter within the patient can bedetermined by x-ray. Alternatively, the entire catheter may beimpregnated with a radiopaque material. The catheter preferably hasindicia in the form of a metric scale 17 which can be observed by thephysician to determine the extent to which the catheter has beeninserted.

The distal end of the catheter is open. An externally threaded, tubularmale coupler 16 is tightly secured in the open distal end of thecatheter. Preferably the coupler 16 is glued in place to prevent itsaccidental dislodgement. To facilitate insertion of the catheter into avein a removable stiffener 18, such as a stainless steel wire, may bepositioned in the catheter during insertion and removed through the openend of the catheter after the catheter is installed.

Referring to FIG. 2A, the coupler 16 is adapted to be threadably engagedwith the internally threaded proximal female end of a tubular flowreducing adaptor 20. Adaptors with different flow reducingcharacteristics are available. The adaptor 20 has an internal fitting 21with a small flow reducing orifice typically in the range of 16 to 27gauge. The distal end of the adaptor 20 is fashioned to be coupled tothe standard male fitting 22 (FIG. 2B) of an intravenous drip mechanism.The flow reducer is additionally threaded on its distal external surfaceso as to threadably accept a cap 24 (FIG. 2A) which may be utilized whenno intravenous fluid therapy is being administered.

When the catheter is being used for long term therapy the intermediatesection of the catheter may have a surrounding cuff 26 (FIG. 1B) made ofa fabric material such as that sold under the registered trademarkDACRON. As shown in FIGS. 6G and 6H the cuff 26 is placed on the longterm catheter such that it will be located in the subcutaneous tissueunder the skin where the catheter 10 exits from the body.

Referring to FIG. 3A, a standard syringe 28 has a needle 30 preferablywith a coating 32 of TEFLON (trademark). A tubular sleeve 34 has aninside diameter slightly greater and a length slightly less than that ofthe coated needle. The sleeve can be slipped over the coated needle andthe proximal end of the needle will be exposed (FIG. 5A). As shown inFIGS. 3B and 5C, the catheter 10 is guided through the sleeve 34 andinto the vein with the aid of the internal stiffner 18.

Referring to FIGS. 4A and 4B, the passer includes an elongate tube 36adapted to slide over the male coupler 16 and the distal end of thecatheter 10. The passer also has a tubular tip 38 having a sharp forwardend. The rearward end of the tip has a cylindrical hub 40 with internalthreading for threadedly engaging the male coupler 16 and externalthreads for threadedly engaging internal threads in either end of thetube 36.

When the catheter is to be installed on a short term basis, e.g., for aperiod of roughly three weeks or less, the following method may beutilized. A clearer understanding may be had by reference to FIGS.5A-5D. With the patient in the lying position a vein which has beenchosen in which to insert the catheter is dilated as much as possible,either by applying a proximal tourniquet or positioning the patient in ahead down position so that the vein fills by hydrostatic pressure. Veinswith a suitably large flow of blood therethrough and which are readilyaccessible include the cephalic, subclavian, internal jugular, externaljugular, basilic, and median cubital veins. The skin over the vein issurgically prepared in the usual manner. Local anesthetic may beinjected around the area of insertion.

Referring to FIG. 5A, the needle 30 fitted to the syringe 28 is insertedinto the tubular sleeve 34. The proximal ends of the needle and sleeveare inserted through the skin and advanced until the proximal ends ofthe needle and sleeve enter the desired vein. The plunger of the syringeis slightly withdrawn. If blood is readily drawn into the syringe, thephysician can be reasonably sure that the needle 30 and the sleeve 34have entered the vein. The sleeve is then advanced slightly, heldfirmly, and the needle is withdrawn from the sleeve (FIG. 5B). Thephysician obstructs the distal end of the sleeve, e.g. with his or herfinger, in order to stop the flow of blood therefrom. Prior to insertionof the catheter, which preferably has the internal stiffener 18 inplace, it is filled with intravenous solution to eliminate air from itsinterior. The solution will not flow out the proximal end of thecatheter through the one way valve 12 without a pressure head suppliedby the solution in an IV bottle greater than the valve opening pressure.At this point the catheter is preferably not connected to the IV bottle.

Referring to FIG. 5C, the proximal end of the catheter 10 is insertedthrough the sleeve 34 into the chosen vein, e.g. the subclavian, andadvanced an appropriate distance as required by the type of intravenousfluids to be administered. Next, the sleeve 34 is slid out of thepatient and over the distal end of the catheter (FIG. 5D). If aninternal stiffener 18 had been used it is withdrawn at this time (FIG.5D). The flow reducing adaptor 20 is then threadably secured to thethreaded male coupler 16 at the distal end of the catheter (FIG. 6G-6H).The male fitting 22 of the IV drip mechanism is then secured to thedistal end of the flow reducing adaptor 20 and the solution flows fromthe IV bottle solution through the drip mechanism, through the flowreducing adaptor, through the catheter, out the one way valve and intothe vein.

It is also possible to insert the catheter into the patient withoutfilling the catheter with intravenous solution before insertion. The oneway valve at the catheter tip will remain closed during the insertionand prevent air from flowing through the catheter and causing an airembolism. Once the catheter is in place a syringe partially filled withintravenous solution may be used to aspirate air from the catheter. Thecatheter may be fully injected with the intravenous solution in thesyringe prior to coupling the flow reducing adaptor to the dripmechanism and the bottle of intravenous solution.

When the catheter is in correct position it is secured to the skin nearits point of insertion. This may be accomplished by sutures and/orbandages. Proper location of the proximal end of the catheter ispreferably confirmed by x-ray.

When long term intravenous therapy or hyperalimentation is contemplated,e.g. for periods ranging from three weeks to several months or longer,the following method may be utilized. Referring to FIG. 6A, the patientis put in the supine position; the shoulder and desired catheter exitpoint prepared for surgical incision by shaving and scrubbing withantiseptic solutions. Sterile surgical drapes are applied to isolate thearea of the deltopectoral groove and the desired catheter exit point.Local anesthetic is injected intradermally and subcutaneously in thearea of the proposed incision, the path of the subcutaneous tunnel, andthe proposed catheter exit site. An incision is made through the skinand the subcutaneous tissue dissected to reveal the cephalic vein.Again, other readily accessible veins, such as the jugulars orsubclavian, which empty into the superior vena cava, may be utilizeddepending on circumstances.

Control of the vein is obtained by means of ligatures, clamps, or othermeans. The proximal end of the catheter is inserted into the vein suchas the cephalic, either directly through an incision in the vein or viathe hypodermic needle 30 and external sleeve 34 as previously described.The proximal end of the catheter, preferably with the internal stiffener18 in place, is advanced into the superior vena cava. Proper location ofthe catheter is determined by x-ray as previously described. A ligatureis tied around the cephalic or other vein distal to the point at whichthe catheter enters the vein. The internal stiffener, if present, isthen removed (FIG. 6B). Another ligature is tied around the cephalic orother vein and catheter to anchor the position of the catheter in thevein.

Referring to FIG. 6C, the male coupler 16 at the distal end of thecatheter is inserted through the tube 36 of the passer and is threadedlysecured to the tip 38 of the passer. The tip is in turn threadedlysecured to the distal end of the tube 36. Referring to FIGS. 6D and 6E,the physician grasps the passer and threads it subcutaneously from theincision in the shoulder to an exit point substantially midway down theanterior wall of the chest or some other selected location on thepatient. The passer is guided through the skin at the exit point. Theproximal portion of the catheter is firmly held at the incision in theshoulder while the passer is pulled to draw slack portions of thecatheter through the subcutaneous tunnel. The passer, with catheterattached, is pulled until the cuff 26 of the catheter is locatedsubcutaneously near the opening in the skin at the exit point.

Referring to FIG. 6F, the tip 38 of the passer is unscrewed from thetube 36 and from the male coupler 16. The tube 36 is slid off thecatheter over its distal end (FIG. 6G). Air inside the catheter isaspirated with a syringe and the catheter is filled with an intravenoussolution as previously described. The male coupler 16 is threadedlyengaged with the flow reducing adaptor 20 which in turn is connected tothe male fitting 22 of the drip mechanism coupled to the IV bottle.Alternatively, a cap 24 may threadedly engage the distal end of the flowreducing adaptor 20. The catheter is secured to the skin near the exitpoint with sutures and/or bandages. The incision in the shoulder isclosed.

The intravenous nutrient or therapeutic solution flows by gravity fromthe solution bottle through the flow reducer and catheter and into thevein. The flow is driven by the hydrostatic pressure deriving from theposition of the bottle of intravenous solution in relationship to thetip of the catheter within the patient. The maximum flow rate isrestricted to a safe level by a flow reducing adaptor connected to thedistal end of the catheter. Further control is provided by the specificopening pressure of the one way valve. When the bottle of intravenoussolution is empty, there is no longer a pressure head sufficient to keepthe one way valve open and thus the risk of air embolism issubstantially eliminated. The one way valve at the proximal end of thecatheter prevents retrograde flow of blood into the catheter and theproblem of blood clotting in the catheter and thus stopping theintravenous solution flow is substantially eliminated. It is no longernecessary to have continuous flow of fluid through the catheter toprevent clot formation, nor is it necessary to periodically flush outthe catheter with anticoagulant substances. This device thus eliminatesthe need for costly pumping and flow control devices and eliminates oneof the major hazards of systems requiring such devices.

Even if the distal end of the catheter becomes uncoupled, the patientcannot lose blood through the catheter because the one way valve closesin the absence of internal fluid pressure. Furthermore, the risk of airembolism in such cases is minimal since air cannot travel through theclosed end of the catheter without being under pressure.

The presence of an anticoagulant coating on the surface of the catheterprevents the formation of blood clots on the inside or outside of thecatheter which might impede intravenous solution flow, serve as a nidusof bacterial growth leading to bacterial septisemias, or serve as asource of septic emboli when the catheter is withdrawn.

It is easily possible to measure the patient's central venous pressurewithout allowing reflux of blood into the catheter and without the useof additional manometers or other equipment. This is done by determiningthe vertical distance between the fluid level in the bottle ofintravenous solution and the proximal tip of the catheter at which flowthrough the catheter just stops or starts. The opening pressure, whichis known, of the one way valve at the catheter tip is substracted fromthis value to give the venous pressure outside the tip of the catheter.When the catheter tip is in the superior vena cava this value is thecentral venous pressure to a clinically accurate value.

The apparatus utilizes a minimum number of components. The sleeve of theshort term catheter apparatus can be completely removed from thepatient, thus reducing extraneous hardware and the hazards associatedtherewith. A passer can readily be coupled to the distal end of the longterm catheter and allows for simultaneous subcutaneous tunneling andthreading of the catheter to an exit site on the anterior chest wall.

The distal end of the long term catheter can be readily manipulated bythe patient because of its convenient location, i.e., midway down theanterior wall of the chest or other suitable site. This arrangement isdesirable because it allows the patient to self-administer nutrient orother therapeutic solutions on an intermittent basis.

As shown in FIG. 6H, upon completion of a particular infusion thecatheter may be filled with an anticoagulant solution and the cap 24threadedly connected to the distal end of the fluid flow reducingadaptor. The patient now has the freedom to ambulate without theconstraint of an infusion apparatus connected to him/her. The patientmay avoid prolonged hospitalization by conveniently self-administeringnutrient or other therapeutic agents, including total parenteralnutrition, on an intermittent basis outside the hospital.

Having described the preferred embodiments of the invention, it will beapparent that the invention permits modification in arrangement anddetail.

What is claimed is:
 1. A method of performing intravenous therapy including hyperalimentation comprising the steps:inserting the proximal end of a flexible catheter having a one way valve adjacent its proximal end through the skin of a patient and into a vein having a suitably large flow of blood therethrough; coupling the distal end of the catheter to an interchangeable static flow reducing means capable of restricting flow of fluid, from a source positioned to provide a predetermined fluid head, into said catheter at a rate no greater than a predetermined clinically described flow rate, coupling a source of intravenous solution to said flow reducing means, positioning said source at an elevation to provide said fluid head, and allowing said solution to flow by gravity through said flow reducing means into said catheter and thence into said vein.
 2. A method of performing intravenous therapy including hyperalimentation comprising the steps;inserting the proximal ends of a hypodermic needle and a surrounding sleeve through the skin of a patient and into a vein having a suitably large flow of blood therethrough; withdrawing the needle and stopping the flow of blood from the distal end of the sleeve; inserting the proximal end of a flexible catheter having a one way valve adjacent its proximal end through the sleeve, into the vein; removing the sleeve by sliding it out of the patient and over the distal end of the catheter; coupling the distal end of the catheter to an interchangeable static flow reducing means capable of restricting flow of fluid, from a source positioned to provide a predetermined fluid head, into said catheter at a rate no greater than a predetermined clinically described flow rate, coupling a source of intravenous solution to said flow reducing means, positioning said source at an elevation to provide said fluid head, and allowing said solution to flow by gravity through said flow reducing means into said catheter and thence into said vein.
 3. The method of claim 2 wherein the vein is the cephalic vein.
 4. The method of claim 2 wherein the vein is the subclavian vein.
 5. The method of claim 2 wherein the vein is the superior vena cava.
 6. The method of claim 2 wherein the vein is the internal jugular vein.
 7. The method of claim 2 wherein the vein is the external jugular vein.
 8. The method of claim 2 wherein the vein is the basilic vein.
 9. The method of claim 2 wherein the vein is the median cubital vein.
 10. The method of claim 2 including the step of filling the catheter with an intravenous solution before inserting the proximal end of the catheter into the sleeve.
 11. The method of claim 2 including the step of aspirating the air from the catheter and filling the catheter with an intravenous solution after the proximal end of the catheter has been inserted into the vein.
 12. The method of claim 2 including the steps of inserting a stiffner into the catheter prior to inserting the proximal end of the catheter into the sleeve and withdrawing the stiffner after inserting the proximal end of the catheter into the vein.
 13. The method of claim 2 including the step of temporarily disconnecting the source of intravenous fluid from the flow reducing adaptor, and occluding the distal end of the adaptor with a cap.
 14. The method of claim 13 including the step of introducing an anticoagulant solution through the flow reducing adaptor and into the catheter before occluding the distal end of the adaptor with a cap.
 15. A method of performing intravenous therapy including hyperalimentation comprising the steps:making an incision through the skin of a patient; dissecting the subcutaneous tissue to reveal an accessible vein which empties directly into the superior vena cava; making an incision through the accessible vein; inserting the proximal end of a flexible catheter having a one way valve adjacent its proximal end through the incision in the skin through the incision in the accessible vein and into the superior vena cava; connecting the distal end of the catheter to a passer; threading the passer subcutaneously from the incision through the skin to a suitable exit point in the body; guiding the passer through the skin at the exit point; holding the catheter at the incision through the skin, and pulling the distal end of the catheter through the skin at the exit point; disconnecting the distal end of the catheter from the passer; coupling the distal end of the catheter to one end of a flow reducing adaptor; coupling the other end of the adaptor to a source of intravenous solution having a desired concentration of nutrients and allowing the solution to flow by gravity through the catheter and into the superior vena cava; securing the catheter to the skin at the exit point; and closing the incision through the skin.
 16. The method of claim 15 wherein the accessible vein is the cephalic vein.
 17. The method of claim 15 wherein the accessible vein is the subclavian vein.
 18. The method of claim 15 wherein the accessible vein is the internal jugular vein.
 19. The method of claim 15 wherein the accessible vein is the external jugular vein.
 20. The method of claim 15 including the step of providing a cuff on the catheter so that it is embedded in the skin at the exit point.
 21. The method of claim 15 including the step of aspirating the air from the catheter and filling the catheter with an intravenous solution after disconnecting the distal end of the catheter from the passer.
 22. The method of claim 15 including the step of tying ligatures about the accessible vein to secure the position of the catheter therein.
 23. The method of claim 15 including the steps of inserting a stiffener into the catheter prior to inserting the proximal end of the catheter through the accessible vein and withdrawing the stiffener after disconnecting the distal end of the catheter from the passer.
 24. The method of claim 15 including the step of temporarily disconnecting the source of intravenous fluid from the flow reducing adaptor and occluding the distal end of the adaptor with a cap.
 25. The method of claim 24 including the step of introducing an anticoagulant solution through the flow reducing adaptor and into the catheter before occluding the distal end of the adaptor with a cap.
 26. The method of inserting a flexible catheter into the body comprising the steps of:providing a flexible catheter having a closed end and openings in the wall of said catheter adjacent said end for the flow of fluid, inserting a wire-like member into said catheter and against said end thereof, said member having sufficient stiffness to permit it to be pushed into a vessel with said catheter, making an incision through the skin of a body and into a body vessel, inserting said catheter and wire-like member closed end first through said slit and into said vessel by applying force to said wire-like member whereby the engagement of said wire-like member with said catheter closed end causes said catheter to be drawn into said body and said vessel, and finally withdrawing said wire-like member from said catheter, leaving said catheter end positioned in said vessel.
 27. A method of performing intravenous therapy including hyperalimentation comprising the steps of:inserting a rigid tubular member through the skin of a patient and into a vein, providing a flexible catheter having a closed proximal end and containing a wire in the interior thereof in engagement with said closed proximal end and extending at least substantially to the distal end of said catheter, said wire having sufficient stiffness that it may be pushed through said member into a vein carrying said catheter with it, said catheter having openings adjacent said proximal end for the escape of fluid into said vein from said catheter, inserting said wire containing catheter proximal end first into said member and applying a force to said wire to effect axial movement of said catheter such as to position the proximal end of said catheter in the vein, withdrawing said wire from said catheter, withdrawing said member from said patient while leaving the catheter in position in the patient, and thereafter connecting the distal end of said catheter to a source of intravenous fluid and passing said fluid through said catheter and into said vein.
 28. The method of claim 27 which includes the further step of connecting a flow reducing adapter to the distal end of said catheter prior to connecting the same to a source of intravenous fluid. 